Aerosol Effective Radiative Forcing Accelerates Earth’s Energy Imbalance In Recent Decades - Preprint

[Geoengineering News]

https://www.researchsquare.com/article/rs-7755051/v1

Authors: Tianle Yuan, hua song, Ryan Kramer, Lazaros Oreopoulos, Shiv Priyam Raghuraman, Robert Wood, Mian Chin

16 October 2025

Abstract

Earth’s energy imbalance (EEI), a key driver of climate change, has risen markedly over the last two decades and continues to accelerate in recent years. Greenhouse gas forcing, aerosol forcing, and cloud feedback all contribute to this increase. However, the role of aerosol forcing, particularly effective radiative forcing through aerosol-cloud interactions (ERFACI), remains highly uncertain and closely intertwined with cloud feedback. Here we estimate ERFACI using satellite observations and show it has been an important contributor to the EEI increase over the past two decades. The ERFACI exhibits a significant warming trend of 0.33 ± 0.03W m−2/decade averaged over oceans between 60oS and 60oN. The warming trend of ERFACI stems from a global decline in cloud droplet number concentration driven by decreasing anthropogenic aerosol emissions. It is similar to the combined instantaneous forcing from greenhouse gases and aerosol radiation interactions estimated by radiative kernel calculations. Our results can close the gap between simulated and observed EEI trends while implying a weak total cloud feedback. Our findings have important implications for studying decadal changes, cloud feedback, and mitigation.

Source: ResearchSquare